LONDON — The latest, perhaps greatest royal baby ever (the Anglo-American one) is soon to arrive — and the atmosphere is growing positively (negatively?) febrile here.

Fever being the go-to metaphor the British press like to use when they are readying for royal babies.

The Duke and Duchess of Sussex are expected to give birth soon — any minute, day or week now. (Due date? Late April to early May, we’ve not been told.)

But — egads — Meghan and Harry have gone dark. They’ve zipped their lips. They’ve not shared the intimate details. The press and public don’t know who (the medical team is), or where (the hospital is) or when (the baby will be presented to news service photographers).

According to an April 11 statement from Buckingham Palace: “Their Royal Highnesses have taken a personal decision to keep the plans around the arrival of their baby private. The Duke and Duchess look forward to sharing the exciting news with everyone once they have had an opportunity to celebrate privately as a new family.”

Meghan, the 37-year-old American former TV actress, has disappeared from public view. She hasn’t been seen out in public in, like, forever.

Harry showed up solo on Easter Sunday at St. George’s Chapel in Windsor Castle. Or, as the tabloids put it in big bold letters: “Someone’s missing! Pregnant Meghan is nowhere to be seen as Harry joins The Queen on her 93rd birthday Easter Sunday service.”

Then Harry popped up again Thursday — an unannounced surprise — at the annual Anzac Day Service of Commemoration and Thanksgiving at Westminster Abbey, to honor those from Australia and New Zealand who served the Commonwealth.

But he was mum on everything baby related.

“We know absolutely nothing, which isn’t good,” said Ingrid Seward, editor of Majesty magazine, which follows all things royal. “In 30 years of covering this kind of news, I’ve never known so little.”

Why the couple has become so press shy about an event widely seen to belong in the public domain could be related to their fraught relations with Britain’s tabloid press.

We’ve been told that the pre-babied Super Couple have decamped from their newlywed digs at Kensington Palace in London and are now nesting (hiding?) up at Frogmore Cottage (not to be confused with the bigger, better Frogmore House) on the Windsor Castle grounds in Berkshire.

The Sun’s royal correspondent, Emily Andrews, tweeted in November that the cottage needed “major building work to turn it back into a luxury family home, boasting 10 bedrooms & a new nursery plus space for a gym & yoga studio.”

There is some contention about the number of bedrooms. And a suggestion that the nursery will “be a monochrome palette — whites and grays.”

The couple have moved in to Frogmore Cottage in Windsor. (Gor/Getty Images)

What other scraps do we know? Not to expect an immediate mass-media photo op.

When Harry’s brother, Prince William, and Catherine, the Duke and Duchess of Cambridge, produced their heir and spares — George, Charlotte, Louis — they did so dutifully at the Lindo Wing of St. Mary’s Hospital in London.

Kate literally gave birth while the press slurped tea and munched buns and did live stand-ups about the comings and goings of the duchess’s hair and makeup team.

Prince William and Catherine appear with their baby son outside the Lindo Wing of St Mary's Hospital in July 2013. (CATHAL MCNAUGHTON/REUTERS)

Then, after just a few hours, Kate with baby appeared — “camera-ready in heels” — to pose for the hundreds of camera crews, who had paid for their spots.

Meghan isn’t likely to repeat.

The silence from Harry and Meghan has created a vacuum, which both nature and the British tabloids abhor, and so it has been filled with all kinds of speculation.

For example, that the headstrong (read, American) Duchess of Sussex “has delivered an astonishing snub to the Queen’s highly-regarded doctors, insisting she doesn’t want ‘the men in suits’ to oversee the birth of her first child,” the Mail on Sunday reported.

Instead, according to the Daily Mail, Meghan is plotting a midwifed home birth, possibly in a bathtub at the cottage, forgoing ye olde epidural for “relaxation techniques such as hypnobirthing, which Californian Meghan — who very much favors alternative therapies — is believed to have been studying with Harry.”

A debate about home births followed, with opinions like the one in a Guardian column: “Meghan Markle’s home birth should not blind us to the risks for most women.”

Then there’s been the speculation about baby names. The Daily Express went with this headline on Thursday: “Royal baby name REVEALED? The shock name bookies predict Meghan Markle will call daughter.”

The shocker was: Grace?

The bookmakers listed Elizabeth and Diana being the favorites for a girl. For lads it was Albert and Arthur. Far down the list: Voldemort, we might guess.

In one sense, the birth of Baby Sussex (title pending, per the queen) is not terribly important, monarch-wise. The heir-tyke to the throne will join a long line to succeed Queen Elizabeth II. Seventh in the queue, in fact.

But in global celebrity news terms, it is a big deal.

Baby Sussex will be half-American and may choose to hold dual nationality, as Meghan remains a U.S. citizen while waiting for her British citizenship to be approved.

(Meghan and Harry are “reportedly not opposed to an American nanny — or a male nanny,” according to breathless tabloid reports.)

A pin commemorating the wedding of Prince Harry and Meghan Markle is attached to a U.S. flag in Windsor. (Frank Augstein/AP)

The cone of silence, this veil of secrecy from the couple, is largely blamed on Harry by royal watchers.

Why? The answers to Harry’s reticence may be found in a traffic tunnel in Paris, where his divorced mother, Princess Diana, died in a high-speed car crash in 1997, beside her lover Dodi Fayed, chased to the end by paparazzi.

Junor imagines the royal couple are “cross and hurt, and decided to do things their way.”

Harry is feeling protective, Harry may be feeling . . . a lot.

“Because the media were very nice about Meghan to begin with, and then in very short time, the honeymoon was over,” Junor said. They turned on her.

The tabloids wrote that Meghan was “difficult” and “high-handed,” that she had alienated staff and was brusque. (So American!)

The British press also focused on Markle’s problematic father, Thomas, who insisted (on “Good Morning Britain” with Piers Morgan) that his daughter had abandoned him.

Meghan called her father out — and her letter to him was leaked. It began, “Daddy . . . Your actions have broken my heart into a million pieces.”

Maybe we should all just busy ourselves with other tasks, but of course we will not. And in Britain, at least, the birth of a royal has long been a cause for celebration.

In more innocent times, Queen Elizabeth II delivered all her children at home. When she gave birth to her second son, Prince Andrew, courtiers simply posted a note on the forecourt of Buckingham Palace announcing the event.

It took another week for a photo of the baby to be released by the palace. Nobody was camped out anywhere, waiting.